


Only Fire and One Human Live Here Now

by R_J_Hatchet



Category: Undertale (Video Game)
Genre: All Humor, And they were soulmates, Multi, No Angst, Polyamory, Polyamory Negotiations, Reader Is Not Chara (Undertale), Reader Is Not Frisk (Undertale), Reader-Insert, Reverse Harem, Soulmates, Tags under construction, and they were roomates, you are going to have a reverse harem so help me
Language: English
Status: In-Progress
Published: 2020-02-14
Updated: 2020-02-19
Packaged: 2021-02-27 19:00:21
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,554
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22720606
Author URL: https://archiveofourown.org/users/R_J_Hatchet/pseuds/R_J_Hatchet
Summary: You and your pal Sansy were working on bringing his daddio back from the void... instead of bringing the goopster back you manage to summon a brighter motley crew. Good thing you and your roommate, the Grillman himself, got such a big house.Whoo, it's going to get hot and steamy, good thing it's winter in the Rockies and you have a big bad ass air conditioning unit installed.The world needs more fireman harem. There's just not enough for me to be satisfied. I will give you a few promises upfront: NO ANGST. NO SERIOUSNESS. ONLY GOOD FEELS AND FOOD. ALSO AN OBLIVIOUS READER. GRILLBY WILL SAY FUCK....eventually.
Relationships: Grillby (Undertale)/Reader
Comments: 35
Kudos: 249





	1. The time you ducking* cursed autocorrect

**Author's Note:**

  * Inspired by [The Fires of Life](https://archiveofourown.org/works/20449952) by [Designated_Traitor](https://archiveofourown.org/users/Designated_Traitor/pseuds/Designated_Traitor). 



> I'm thirsty for that magma man. Deal with my self indulgence. Im not taking this seriously, so honestly, neither should you. But hey, if I do a half decent job.... your welcome. 
> 
> Sorry about all the Grillby AU descriptions below, I wanted to get a good picture of what each individual looked like down cause for at least swapfell and horrortale it seems like no one can agree.
> 
> I MIGHT expand the hot boi army later if I feel its warranted, but for now, enjoy being doted on by five flaming hot men.

The buzzing of machinery and the snapping of electricity filled the room as you shuffled through the scribbled research notes, giving them one final look over. Physics wasn't exactly your forte, much less quantum physics, but hey, it was always good to get a second opinion before you potentially poke a hole into another dimension.

As a chemist, the whole concept mostly went over your head, but you were all for lending a hand to your bestie in his time of need... that time being that Alphys was apparently busy out on a date night with the fish wife, according to Sans. And for once in his life, he was in a bit of a rush and didn't want to wait.

Sans was lucky that you were coworkers, besties, and that you totally owed him one for introducing you to your roommate. 

Speaking of said roommate, Sans was also lucky Grillby wasn't in charge of making dinner tonight, or you would have been busy too. After living the past fifteen years of your life off of microwave meals and take out, nothing on the face of the earth would make you miss out on one of your roommates decadent meals. Just thinking of his cooking skills makes you a little hot under the collar. 

Getting back to the matter at hand, you flip the page to show a diagram of a dial, and since Sans' notes are _so_ well organized, it only takes you a small eternity to find the corresponding part on the machine. It looked a little off to you, and you decide to bring it to your lab partners attention.

"Are you sure that nob is supposed to be turned all that way? In your notes it says that the dial needs to be at exactly 3.1415 degrees from.... the cake symbol?" You mentioned looking from the oddly decorated dial back to the notes.

A muffled voice responds back from underneath the massive machinery "that's supposed to be a pi symbol. and its where it should be. don't worry pal, that's the old formula... i found it was a little under cooked.".

It takes you a moment to cue in the reference. A cold stare is directed to where the voice originated. "It's a useless knob that you put there just for that half baked joke isn't it?"

A snicker is your only response before your skeletal companion rolls himself out from under the contraption. His eternal grin is still stretched wide across his skull before he meanders over to your side at the control panel.

"welp, with that last adjustment we should be ready to go. you remember what I needed you to do right?" He asks giving you a side look as he flipped up the plastic covering to a large orange button. His other hand was ready to dance across the necessary switches for a smooth activation.

"Well yes, but... are you sure you can't wait for Alphys to look this over?"

"positive."

With a sigh you situate yourself infront of the keyboard input, giving Sans a nod. You just needed to do one thing, hit a few keys and slap the enter button. Sans would have done it himself, but he's going to be a tad busy to the side making sure that the whole world doesn't collapse on itself from the startup process.

With a whirr, the machine burst to life. And your hands hovered, waiting anxiously for the cue to come. With a buzz your fingers flew over the keys tapping away as fast as possible, you could see your input in the small dialogue box displayed on the screen.

G.A.S.T.E.R. enter

Loading....

Loading....

Autocorrect ingaged....

Wait what?ohfuck! "Sans!"

Searching for alternatives...

"sup?"

"Its autocorrecting the entry!"

Alternatives found...

"oh shit. probably shouldn't have repurposed your phone drive."

"YOU DID W H A T."

Searching through contacts...

"Sans WHO THE FUCK thinks it's a good idea to use the drive from a phone?!"

Contact found...

" i ran out of drive space, i needed something small and you know mine is still on dial up."

Initiating retrieval process...

"Ohmyfuckinggod! Well turn it off!"

"can't, it's too unstable, we risk blowing up if it stops now."

Retrieval initiated...

"Shiiii-"

C R A C K

A concussive blast of light and heat imits from the machine, the wave blows you over and away from the controls, tossing you to your back on the ground. Your ears ring as your head throbs from the impact. You lie there on the cold basement floor as you wait for the throbs to dull to a small ache.

After the moment fades you sit up groaning, ears still ringing, but the light and heat have died down to a manageable amount. You crawl over to the controls and use them as a brace to lift yourself up.

As you do so, you get a look at where the heat and light are coming from. Your eyes widen in shock before you try to locate your lab partner. You find him flipped upside down against tone of the basement walls.

"SANS" you call, though it sounds quieter than usual.

"what?"

His voice sounds like a dull murmur to you. You stumble over to help right him.

"YOUR TAB AT GRILLBYS JUST QUINTUPLED."

"that's mean pal, don't pull gurbz into this."

His voice and your own are still softer than they should be. As you lift him up, you turn him around to look at the heart of the issue.

" I DIDNT, YOUR MACHINE JUST DID."

Infront of the two of you, are five familiar fellows. One is very clearly the Grillby you know and live with... and he's looking at you and Sans with as deadpan an expression as flames can get. In his hands was a spatula and a pan filled with a half cooked burg. You knew from the slow flickering of flame on his head that he was displeased about being pulled from work, and you were going to be getting a stern talking to later about going along with sans' boondoggling.

The other four surprised guests in front of you could very easily be brothers to Grillby, looking near identical in all but color and cloathing.

The first also had a pan in hand, though it looked like the classic burg was not on the menu. His flames were a bright purple with blue sneaking in at the flickering ends. He had a leather coat with what looks like a white fur collar tied around his waist covering black pants. His black pinstripe dress shirt had sleeves that were rolled up and the collar popped, a much more relaxed look than you've ever seen Grillby pull off at work. He also had a bit more of an angry gangster feel than you were expecting, his flames flickering a little higher and faster than you've ever seen on Grillby.

The second was more of a yellow flame than orange and it went quite well with his bright yellow undershirt and large red bow tie. His blue suit coat and pants made for a nice pop and kept his whole pallet very fun. His glasses were round swirls and much like the other Grillbys, he had some wares in his hand. A tea kettle and a cup being held by a saucer held something that shone a bit brighter than regular tea would, and you couldn't help but wonder what it tasted like. Though confused, this fire man seemed a little more chipper about his situation, eyes behind his glasses wide and head tilted slightly.

The third was more of a magenta than a purple, and was wearing what appeared to be a dark purple three piece suit that would have fit in the Victorian era, he even had that ruffled thingy what was it called... an ascot! As if he wasn't dapper enough, he also wore a monnacle instead of full glasses and had a cane tucked into the crook of one arm. His demeanor was of a proper gentleman... if gentlemen would stab your back with a grand smile, something you felt you might need to look out for what with the current irritated grin. In his hands was a baking sheet, though you couldn't see what was on it.

The final of the quintet had you feeling worried, not for yourself, but for him. His cloathing was the closest to your familiar Grillbys, but it was tattered and fit poorly on his frame. He appeared almost swamped in the loose fabric, and to make matters worse, his flame was a pale grey white and barely immited any light. He had nothing in his hands and you saw them visibly shaking. The urge to hold his hands and pet his poor smoking head was growing more intense as you saw him nervously flick his head around the room.

After observing the motley crew you raise a hand up giving a small half hearted wave to the crew. You feel your sins crawling up your back as all of them take notice of you and turn to stare you down.

"UH, I PROMISE IT WAS AN ACCIDENT, AND WAS MOSTLY NOT MY FAULT?"

Yeah, your pretty sure that an explanation ike that wouldn't be good enough to appease one Grillby, much less five almost clones.

"hey pal, your paps impression is pretty good, but kind of over the top right now."

You furrow your brows as your thought process is interrupted, looking down at you skeletal pal. "SANS, IF I WAS ATTEMPTING TO IMITATE YOUR BROTHER, ID BE THROWING IN MORE NYEHS AND THE GREATS. ALSO, I'D BE SHOUTING, WHICH IM NOT... YOURE JUST WHISPERING."

You watch as Sans' eyesockets widen before he looks up at you and then back to the fire troupe.

He better not...

He side eyes you one last time and you get the feeling he's about to dump a problem on you to handle.

Hoe don't do it...

You reach out to grab his shoulder as he-

"be right back bud."

-disappears.

You purse your lips to hold in the scream of rage as you count backwards from ten and turn to greet the rest of the group with a forced smile.

"SO... WHOS UP FOR LUNCH AND A AWKWARD EXPLANATION?"

**Notes for the Chapter:**

> No beta we die like men!.... though we don't want to..... And I wrote most of this on my phone at the drop of a hat so yes, there will be issues.
> 
> Kudo if you wish, subscribe if you desire, and comment at your own digression.... just know that each action feeds the beast and makes me more powerful... you have been warned.


	2. The Explanation(tm)

**Summary for the Chapter:**

> Enjoy awkward cringe moments? Good, have some more.

**Notes for the Chapter:**

> Yall came out like a frickin GASTER BLASTER at that chapter, what the hecky. If you keep this up imma get a swoll head.
> 
> So I'm already writing chapters in advance cause if I don't do it now, I will lose steam, but the muse is fresh and ready to rumble, so expect updates almost weekly... barring natural disaster and all that jazz.
> 
> With that said: ENJOY ENTERTAINMENT BABIES.

One awkward and shouty shuffle later and you managed to get the crew up out of Sans' creepy science dungeon and up to the living room. 

All of you were situated around the room, lounging in various states of comfort across the furniture. Your Grillby was situated on the couch next to you, and you appreciated the show of support at this time. It seemed that you were all spending your time awkwardly staring at anything but eachother. 

Grillby had pointed out that you were shouting on your way up to the living room, so you were a little to embarrassed to be talking at the moment. apparently the explosion burst your eardrums, so your hearing would be out of whack for the next little while.

Regardless of your hearing though, the house around you was quiet... too quiet. 

Sans probably picked this time to do the experament because his brother was out for the night with the monster ambassador, which ment no awkward explanations to energetic skeletons.... as of yet.

You coughed into your fist to try and help break the ice. Of course you then felt the blazing eyes of all five men on you which made your embarrassment level rise. 

"ALRIGHT- Ahem, I mean, alright? Yes, that's better." You try to adjust down your volume until you notice small nods from some of the group. 

"Im sorry that you were all dragged away from your respective works, I know that this is definitely not what you planned on doing this evening..."

"Ye've got that fucking right." You manage to barely hear this from the grumpy looking fire fellow.

"...Yeah...since I am the only person currently available to do so, we are going to have to go over this event together, and gather all the information we can about what happened. This way we can get everyone back to their regularly schedualed evenings without any further explosions or side effects."

You look around the group and most seem to be amicable to your suggestion. 

"Excellent, so let's get step one out of the way, what is everyone's names? I know Grillby, but I didn't know that there were so many other fire elementals in the monster populace, it's very exciting to meet you all."

"There isn't... from what I know there was only supposed to be...Fuku and me left." The white one murmurs, looking down about the fact. "I am Grillby..."

Wait...

The bright and cheery one pipes up next "Oh, and Heats Flamesman, if you remember to include him~. I'm also Grillby, nice to meet you!"

Wait what...

"Tch, Flamesman barely counts as a fire anything, let alone an elemental. And there ain't no other Grillby 'cept me." The rougher purple Grillby declared with a huff.

It's got to be your hearing... it has to be...

"Ahem, perhaps in your booneys your the only Grillby, but the true Grillby is me aheheheh~." The dark and dapper Grillby gives a snicker behind his gloved hand.

Yeah, that's what you thought you heard.

"Little light...exactly what did you and Sans do?"

You flinch at the question, how are you supposed to answer something you didn't really understand? Due to how the machine worked, and what you were trying to do, the actual events that occurred were well outside of what you were knowledgable of.... or remembered, which occurs quite frequently with the realm you were messing with.

F̶̨̨̣̘̖͉̱̳̜̭̩̍́̎̔̎͌̇͐̑̓̾͜ứ̴̩̼̦̯͇͕̝̺͙̖̟̝̝́̀̓̈́̄̋̋̇̓c̷̯̐̿̄̅̈́̌͒̎̃̅̊͗k̴̢͈̼̾ȋ̴̠͙̳͍̗̫͉̲͕͉̜̫̟̻͔̏͆̈́͑̓̾̇͑̉͂͆́͗̕ͅn̵̡̢͕̜͍͓̭̫̼̞̞̣̱͚̍̌̈́̒̕g̴̡̤̗̮̳̓̊̊̆͑̈̆̊̄̀̔̈́̅̐̍̕͝ ̴͉͔̼̼̪̟̦̋V̴͙̻̥͚͍̯͕̦̒̾̍͗̋̿̾̎̇̄̍̃̌͘ǫ̴̢͖̹̙͔̰̼̑͆͊͂̄̎͊͗͋̾i̶̧̧̧̙͔͉͕̘̙͓̞͈͚̖̼̬͚͇͉̙̔̿͌̅̽̔͌̈͌́̄͒̊̇̓̈́͗̋̕d̷̮̄̎͌̀̆̿̓͆͌͌́̓͂̍͘͘ͅb̴̗̼̙̝͎̹̼͖̖͕̽̑̌̆̌͌̊̂̆̎̔̑̃̈̎͝ͅư̸͓̹̿͆͛͋̈́̿͂̈́̌͗̀̎͐͝͠͝l̵̠̙̦̥͕̰̲̱͑̈̄͜͠ͅl̸̨͚̪̟̳̗͚̭̺̗̣̝̪̟͈̤̲̳̾͒̾͑̓̿̐̒̇̑̒͒̅̈́̉̈́́̕͘͠ͅş̷̨̢͇̟͓̮͉̘̠̮̫̊̓̈́͗͂̒̏̚͜h̷̢͓͖̻͉̗̟̼͓͔̭̱̦̳̔͛̐͊̏͋͐͗̅̌̒̈́̿̈͒̓͆͑͝ͅͅi̷̢̨̢̛̝̩͔̱̝͓̯̰͍̫̫̙͎̞̦̱͍͂̇̋̇̍͑͋̍̈̌̓͘͜͝ţ̸̧̡̥̹͙̗͖̳̺̞̖̯͈̜̖̞͇͒́̌͋̈́̉̈́͛͠͝͠ͅͅ

You look to the Grillby you know, shoulders slumped. "I... wish I knew Grillby, but it was a but above my pay grade, and I was doing this pro bone-o as a favor to Sans." Oof, you knew you were feeling distressed when you slammed two puns into one sentence.

You could physically feel the disappointment coming off of Grillby, and it made you worried about your future meal quality. Lunch, it seemed, was no longer on the menu...If this whole thing also cost you the delicious mac and cheese bites Grillby made you on off days, you were going to cry.

"technically, all we did was prove that the multiverse theory was true. we just dialed the wrong number."

You whip your head to face Sans' barely audible voice, mouth open to ask for details, but you choke on a gasp as he flicks a monster candy down your throat.

You swallow the small sweet and feel the warm tingle of magic sweep through your veins. You feel your ears pop before clarity cuts through the muffled sounds from before. 

"we had the settings right for everything except the recipient. apparently, we didn't have the latest text pack update, and o the machine couldn't read the name entered..." 

Your eyes narrow knowing where this is going. "And because you used a phone as one of the parts, the machine went through the contacts searching for the closest match... didn't it?" 

"in layman's terms, yup. it also fried the machine, which means that i have to replace a few of the parts before we can try again."

Sans pauses before looking around the room at the displeased or slightly murderous expressions. He nervously starts sweating before continuing his explanation. "...or send them back to their universes. and with how hard some of those parts are to make, it's going to take a ton of time..."

"Sans no..."

"a skele-ton."

Fuck, theres a time and a place dude! Only you are allowed to pun under stress.

"I hate you."

You run your hands down your face as you try to hold in your screech, zoning out from the mess of a situation in front of you.You now know what it feels like for Paps and why he does what he do.

A few calming breaths and relaxation techniques get you back to your version of normal as you think over what you understood from Sans' explanation.

"Okay, so TL:DR, the Grillby crew, who are all the only Grillby from their respective Universes, are now here in this universe and will be for some time. Do I have that right?"

"yeah."

"And with monster/human relations the way they are, getting them citizenship papers this late after the whole mass mountain exodus is not going to go smoothly. And that means they won't be able to get legal housing... which means we are going to have to own up to our mistake and house them."

"yup."

"... and you being a lazy asshole are going to foist them onto me and Grillby because unlike you, we actually have spare rooms and no questioning little brothers."

"thanks for volunteering."

Don't get mad, don't get mad, don't get mad. Just as you go to point out a few flaws is Sans' assumption, another voice cuts in.

"Well ya little shit, ye've forgotten something in yer fuckin plannin sesh. What the fuck we think."

You go purple grumpy gangster Grillby, you tell him what's up! You're not going to turn down help when it comes to this.

"Indeed, I do believe that there is more to this than you've taken into account. Such as what you ment by monster human relations, why haven't you brought this one to queen Toriel afufufu~?"

Eh? Wait a moment, does that mean that Mr. Brightside Grillby's monster population is still underground? Oh crap.

"...We made it to the surface, we have been free for about two years now." 

Your Grillby's quiet statement seemed to shock the other four, but it seemed to hit the white one the worst. You visibly saw him start to quake, and his arms wrapped around his torso, almost like he was protecting himself from the news. After a moment of quiet awe, you hear a shaky voice pipe up.

"... What if we never want to go back?"

Aw shit. Say no more my dude, you have clearly gotten the picture that all is _not well_ in that dimension. Before you realize it, you've taken white Grillby's hands, startling him. You watch as a shocked expression goes across his face before he freezes up stiffer than a board. His flames are barely flickering and you try and gently rub over the backs of his hands to relax him. You think it starts to help because his hands are getting warmer and his face is starting g to get more of a healthy glow going... that's how you know it works right?

"No one is going to have to leave unless they want to. I promise." Says the chemist that has no idea how dimension hopping works.

But fuck it, if you needed to, you were going to make yourself a dimensional alternative universe specialist. If you had to buy weird string theory books and actually read them instead of skim, you'd suffer through the pain. You'd binge read all of the sci-fi book series you know Sans had stashed away if you had to.

You'd make sure that they got what they wanted...Even if... even if it cost you the one thing you loved most: breakfast in bed on Sundays. You would sacrifice it for your roomates alternate selves, you owed it to him... or was it them?

"Regardless of that, what if we don't want to stay with lesser copies of ourselves in such a confined room hmmm? I'm certain the this human and clone don't have enough room to house us to the standard we are used to, Ahehehe~"

Magenta Grillby nooo... this is not how you win friends and influence people! And how dare he make assumptions like that, he don't know who you are, he don't know your story! Best fix this error now anyways. 

"Pft, I'll have you know that our house, much like my bank account, is dummy thicc, we have more than enough guest rooms to house everyone. Besides, your lost in a foreign dimension, where _else_ would you stay?"

Not exactly your most mature moment, but at least you stopped yourself from calling him a peasant and lifting your nose into the air. It also gets the point across that although this isn't the best situation, it's what he has to work with.

Displeased is putting the look you get lightly at that comment, and you see that Grillby visibly clench a fist around his cane with audible sizzles coming from his flames.

"Besides, even if I want you to stay at our place, I still have to run it past my roomy, and I'm not sure exactly how giving he's going to be feeling right now." You look to your Grillby, he's always been a man of few words, but even this is a bit quiet for him.

You feel a warm hand on your shoulder and you drop White Grillby's hands - you have to come up with better names than colors - and turn to fully face your Grillby.

"We are going to have to talk first."

Oh no, you are definitely in the figurative dog house. 

**Notes for the Chapter:**

> Maybe next chapter we'll actually have..  
> . Distigishable names * GASP* Nah but seriously, I've been workshoping some decent names. 
> 
> Yet again, I got no beta reader so yall gonna have ta cool yer jets about my errors.... unless you want to step up and take over the empty positionthat is. I'm writing on a phone, and like an idiot, barely double checking my work before hitting send, so yeah, that's a nightmare situation.
> 
> YOU'VE ALL FED THE BEAST, NOW LOOK WHAT YOU'VE DONE, YOU'VE MADE AN OVERPOWERED WRITING DISASTER. Don't worry though, if we all stop giving comments and kudos, the beast might run out of gas eventually. AND SOMEONE GET THE SUBSCRIBERS ON THE PHONE, WHAT THE HELL WERE THEY THINKING?!

**Author's Note:**

> No beta we die like men!.... though we don't want to..... And I wrote most of this on my phone at the drop of a hat so yes, there will be issues.
> 
> Kudo if you wish, subscribe if you desire, and comment at your own digression.... just know that each action feeds the beast and makes me more powerful... you have been warned.


End file.
